An experimental test of the physiological consequences of avian malaria infection
Bibliographic record
Abstract
Chronic, low-intensity parasite infections can reduce host fitness through negative impacts on reproduction and survival, even if they produce few overt symptoms. As a result, these parasites can influence the evolution of host morphology, behaviour and physiology. The physiological consequences of chronic infection can provide insight into the processes underlying parasite-driven natural selection. Here, we evaluate the physiological consequences of natural, low-intensity infection in an avian host-parasite system: adult male red-winged blackbirds (Agelaius phoeniceus) infected with haemosporidian parasites. Chronic haemosporidian infection has previously been shown to reduce both reproductive success and survival in several avian species. We used antimalarial medications to experimentally reduce haemosporidian parasitaemia (the proportion of blood cells infected with haemosporidian parasites) and measured the effect of treatment on body condition, haematology, immune function, physiological stress and oxidative state. Treatment with an antimalarial medication reduced parasitaemia for the most prevalent haemosporidian parasites from the genus Plasmodium. Treatment also increased haemoglobin and haematocrit, and decreased red blood cell production rates. We detected no effect of treatment on body condition, immune metrics, plasma corticosterone concentrations, total antioxidant capacity or reactive oxygen metabolites. Our results suggest that the damage and replacement of red blood cells during infection could be important costs of chronic haemosporidian infection. Strong links between parasitaemia and the physiological consequences of infection indicate that even for relatively low-intensity infections, measuring parasitaemia rather than only presence/absence could be important when evaluating the role of infection in influencing hosts' behaviour, physiology or fitness.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".